Re: [PATCH v2 06/21] KVM: x86: Treat #DBs from the emulator as fault-like (code and DR7.GD=1)

[Sean Christopherson]

On Wed, Jul 06, 2022, Jim Mattson wrote:
> On Tue, Jun 14, 2022 at 1:47 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
> >
> > Add a dedicated "exception type" for #DBs, as #DBs can be fault-like or
> > trap-like depending the sub-type of #DB, and effectively defer the
> > decision of what to do with the #DB to the caller.
> >
> > For the emulator's two calls to exception_type(), treat the #DB as
> > fault-like, as the emulator handles only code breakpoint and general
> > detect #DBs, both of which are fault-like.
> 
> Does this mean that data and I/O breakpoint traps are just dropped?

Yep.

> Are there KVM errata for those misbehaviors?

Nope.

> What about single-stepping? Is that handled outwith the emulator?

Single-step is emulated, and AFAIK there are no _known_ bugs.